. >>> scientists from japan have made a breakthrough in reproductive technology. they use multipurpose stem cells to generate female reproductive cells. then they produce mice. they hope what they learned might someday lead to the treatment of infertility. rnlers at kyoto university took the cells of female mice to produce ips cells. they apply a protein to them to develop what are called germ cells. the researchers transplanted the germ cells into ovaries. they succeeded in generating reproductive cells, or to va. they fertilize the ova with normal sperm. they placed them in mice, waited, then the mice did what the team hoped for -- they gave birth to normal offspring. >> translator: we are reproducing the mechanisms of sperm and ova in test tubes. research on chromosomes has helped identify cause of infertilit infertility. this achievement will improve our chances of finding a cure. >> the group succeeded last year in generating mouse sperm from ips cells. saito says researchers need to be careful about what they do next. >>> earlier, we spoke to the reporter wh